2D Numerical Simulation of Fluvial Hydrodynamics and Bed Morphological Changes

In this paper, the application of numerical simulation for Computational Fluid Dynamics (CFD) in river Hydrodynamics is represented. In this regard, a case study was carried out in an intended area along the Karoun River-Iran, using the CFD model, CCHE-2D. After giving the geometry domain of the field under the study, the depth-averaged Reynolds approximation of the Navier-Stokes equations, were employed to solve the flow field. Furthermore, the standard k - epsilon turbulence model was used to simulate Reynolds's shear stresses and to close the governing equation systems. A finite element procedure was used in order to solve the equations. Applied equations were used to consider the effects of secondary flows on flow field at meandering reaches. The sedimentary transport assuming non-uniform material at a non-equilibrium state was calculated. The depth-integrated convection-diffusion equation of the suspended load transport and the continuity equation of bed load were solved. When the non-equilibrium transport model is adopted for bed load, the calculation of bed change determined by the overall sediment continuity equation. To verify the numerical results, Stage-Discharge curves resulted from the numerical simulation was compared with the measured data at the Karoun hydrometric station and the qualitative erosion pattern is compared with the river sedimentary process. Comparisons show the results balance. The data obtained also show that the used model has an efficient capability in river engineering simulations, especially in predicting flow field. Furthermore, the erosion and sedimentary pattern of the region show the high erosive characteristics of the studied area in the river against probable floods.